For centuries, the prevailing belief was that the adult brain was immutable to change. The concept of neuroplasticity—the brain's ability to change functionally or structurally—was thought to stop by the age of 25. However, today, clinical research has overturned this idea, showing that, when the brain is stimulated by certain activities and experiences, the adult brain can indeed continue to develop well into old age. Furthermore, recent studies have revealed that the mature brain undergoes functional and structural changes on a monthly basis as well, influenced by menstrual cycles. These discoveries underscore the importance of developing more brain-based solutions to optimise wellbeing.

In a world flooded with products, activities, and marketing claims suggesting they can boost neuroplasticity, it can be difficult to distinguish fact from fiction. Many individuals are enticed by promises of enhanced cognitive health, despite minimal scientific evidence. For this reason, this article aims to delve deeper into neuroplasticity, with a specific focus on the cycle-brain connection. We begin by exploring clinical research on well-known practices alleged to promote neuroplasticity, critically evaluating the evidence supporting these claims. It then investigates emerging technologies like Nettle and whether the research supports claims that such technology can enhance neuroplasticity, thereby improving menstrual and overall well-being.

Thanks to advancements in neuroimaging, scientists can now directly observe neuroplasticity in action. This breakthrough is invaluable for clinical studies examining the impact of specific activities on brain health, lending scientific credibility to longstanding beliefs about wellness. Take physical exercise as an example: its benefits have been celebrated in medical circles for centuries, with recent emphasis on its positive effects on brain health. Neuroimaging takes our understanding a step further by revealing how exercise promotes brain health, demonstrating changes in neural activity, brain structure and other indicators of neuroplasticity.

For example, research by Erickson et. al found that a year of aerobic exercise can enlarge the hippocampus, a critical area for memory and learning and the first to be affected in Alzheimer’s disease. Similarly, a study by Colcombe revealed six months of exercise training enhances grey and white matter volumes in areas critical for higher cognition, which are vulnerable to ageing. Beyond structural changes, a recent meta-analysis showed that physical exercise also increases neuroplasticity via neurotrophic factors and in turn leads to improvements in cognitive enhancement of learning and memory. What is clear, at least from the example of physical activity, is that we can in fact, at any age, change our brain structure and activity.

The same can be said for mindfulness meditation. A group of researchers from Harvard Medical School demonstrated that when compared to no meditation, an 8-week mindfulness-based training program led to increases in the grey matter volume in several brain areas including the posterior cingulate cortex, temporal areas and cerebellum – all of which are key regions for learning, memory, and emotional regulation. Another study showed that long-term meditators as compared to non-meditators have a greater number of neurons within the regions responsible for attention, and self-control. Moreover, evidence from a randomised controlled trial in older adults, led by a group of investigators from Boston, has found that an 8-week mindfulness intervention resulted in improvements in cognitive performance and increased connectivity within the brain’s network known as the default mode network (DMN), which is highly susceptible to age-related neuronal loss.

Interestingly, the brain is not only able to adapt to changing conditions in long-term processes such as a 6-month-long exercise routine or 8 weeks of mindfulness training, but it also does so on a monthly basis.

Hormonal fluctuations during the menstrual cycle play a significant role in neuroplasticity. Research, including studies by Barth et al, has shown variations in the hippocampus' plasticity correlating with the menstrual cycle, particularly noting increased brain connectivity with rising oestrogen levels in the period before ovulation. The connection between oestrogen and brain health is supported by studies on early menopause that demonstrate the heightened risk of neuronal loss and increased vulnerability to Alzheimer's disease as a result of oestrogen reduction in the body.

In a recently published longitudinal study, Zsido and colleagues have found that changes in hippocampal sub-regions are closely tied to fluctuations in ovarian hormones. Increases in oestrogen levels have been linked to the expansion of the parahippocampal cortex, crucial for memory encoding and retrieval, while elevated progesterone levels have been associated with increased volume in the perirhinal cortex, important for processing sensory information and memory.

Further research from the University of California at Santa Barbara indicates that follicle-stimulating hormone (FSH) and other ovarian hormones can affect cortical thickness across the brain. The study observed that progesterone levels during the luteal phase can lead to variations in cortical thickness in different regions, suggesting a complex relationship between hormones and brain structure.

If we zoom in on the molecular level, research studies have shown a correlation between oestrogen and increased neuronal plasticity, partly modulated by increased levels of neurotrophic factors like Brain-derived Neurotrophic Factor (BDNF), a molecular indicator of neuroplasticity.

All of these studies demonstrate that the brain undergoes significant structural and functional changes as a result of hormonal fluctuations in the menstrual cycle. These changes indicate that during some phases our brains are "more plastic" than in others.

On one hand, certain activities are known to enhance neuroplasticity, whereas, on the other, natural cycles, such as the menstrual cycle, can have variable impacts on our brain's plasticity. It is therefore reasonable to suggest that engaging in neuroplasticity-promoting activities could be an effective strategy to manage the physical and mental symptoms associated with menstrual cycles. However, the challenge lies in consistently integrating these practices into daily life, as they often require the development of new habits over extended periods. This is the context in which technologies like Nettle may offer valuable assistance.

Nettle is a neuromodulatory device that uses a neurotechnology known as transcranial Direct Current Stimulation (tDCS). It is a non-invasive neuromodulation technique that uses the alteration (modulation) of neuronal activity through the targeted delivery of low-intensity electrical pulses, to brain regions responsible for mood regulation (prefrontal cortex (PFC) and motor cortex (M1) for pain perception.

Although research in the field of tDCS is ongoing, there are promising studies that highlight its potential benefits for managing mental and physical symptoms related to menstrual cycles. For example, recently published guidelines, by clinical and scientific experts in the field, based on a meta-review of clinical studies stated that tDCS is effective for the treatment of depression. Studies also demonstrate that tDCS is a promising and safe alternative pain therapy for the treatment of chronic pain.

Interestingly, a recent study led by a group from Japan showed that a combination of neuromodulation (tDCS) with mindfulness meditation led to a significant decrease in anxiety levels following the intervention in a healthy group of individuals. This suggests promising potential in leveraging a combination of neuroplasticity tools to further enhance their effectiveness.  

The evidence suggests that engaging in activities that enhance neuroplasticity, coupled with the targeted use of neuromodulation technologies like tDCS, offers a promising approach to managing the physical and mental symptoms associated with menstrual cycles. The cycle-brain connection presents a strong case for approaching menstrual well-being with neuroscience. Although research in this area is still in its early stages, strategies aimed at "hacking the brain" to boost neuroplasticity hold significant potential in the field of women's health. We look forward to watching how this space evolves.